<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #d1{
            width: 150px;
            height: 150px;
            border: 1px solid #000;
            background: #EDB21C;
        }
    </style>
</head>
<body>
    <div id="d1" onclick="changeDiv(this)">

    </div>
</body>
     <script>
        function changeDiv(thisobj) {
            thisobj.style.width = "400px"
            thisobj.style.height = "400px"
            thisobj.style.background = "pink"
        }
    </script>
</html>